Influence of the Substrate/Inoculum Ratio on Process Stability and Performance during Batch Digestion of Grass Silage

The impact of the substrate/inoculum ratio on the performance and process stability during batch digestion of grass silage, an important substrate in biogas plants, was investigated. The methane yield, degradability, and evolution of intermediary products were monitored in mesophilic reactors fed with increasing amounts of grass silage. A first‐order kinetics model was also applied. Signs of inhibition were observed for the highest loadings, but the system recovered and process failure was not observed. The methane yield decreased with increasing loading but the system was resilient to high loadings under batch conditions.     

A Novel Coenzyme A Analogue in the Anaerobic,Sulfate-Reducing,Marine Bacterium Desulfobacula toluolica Tol2T

Coenzyme A (CoA) thioesters are formed during anabolic and catabolic reactions in every organism. Degradation pathways of growth-supporting substrates in bacteria can be predicted by differential proteogenomic studies. Direct detection of proposed metabolites such as CoA thioesters by high-performance liquid chromatography coupled with high-resolution mass spectrometry can confirm the reaction sequence and demonstrate the activity of these degradation pathways. In the metabolomes of the anaerobic sulfate-reducing bacterium Desulfobacula toluolica Tol2^T grown with different substrates various CoA thioesters, derived from amino acid, fatty acid or alcohol metabolism, have been detected. Additionally, the cell extracts of this bacterium revealed a number of CoA analogues with molecular masses increased by 1 dalton. By comparing the chromatographic and mass spectrometric properties of synthetic reference standards with those of compounds detected in cell extracts of D. toluolica Tol2^T and by performing co-injection experiments, these analogues were identified as inosino-CoAs. These CoA thioesters contain inosine instead of adenosine as the nucleoside. To the best of our knowledge, this finding represents the first detection of naturally occurring inosino-CoA analogues.     

Coupling System for Food Wastes Anaerobic Digestion and Polyhydroxyalkanoates Production with Ralstonia eutropha

A new technology was developed to couple the anaerobic digestion of food wastes with production of polyhydroxyalkanoates (PHAs). Acetic, propionic, butyric and lactic acids were produced during food wastes anaerobic digestion and their concentrations reached 5.5, 1.8, 27.4 and 32.7 g/L, respectively under appropriate digestion conditions. The fermentative acids were transferred through a dialysis membrane to an air-lift reactor for PHA synthesis by Ralstonia eutropha. Dry cell concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The obtained PHA was a copolymer of b-hydroxybutyrate (HB) and b-hydroxyvalerate (HV) with 2.8% (mole ratio) of HV units in polymer.     

UASB-接触氧化处理高浓度有机废水试验研究

本文主要通过UASB 接触氧化生化处理模型对某化工厂废水的试验研究，探索运用UASB法处理高浓度有机废水的可行性。同时还探讨了废水的CODcr及含盐量对UASB处理效率的影响，以及关键参数的选用。     

分步厌氧-内循环SBR工艺处理苎麻脱胶废水

采用酸析气浮＋分步厌氧＋内循环SBR工艺处理苎麻脱胶废水。硫酸酸析后木素经气浮去除，剩余有机污染物中的大部分通过厌氧生物降解，最后再经好氧生物处理，使出水的COD、SS、色度达到国家规定排放标准。在试验基础上探讨了该工艺的特性，为其在高浓度有机废水处理中的应用提供实验依据。     

山梨酸废水的生化处理

山梨酸生产废水有机浓度高、可生化性好、含盐量高。废水中CODCr为8000-16500mg/L，B/C≥0.5，含盐量≥15g/L。本工程通过淹没式厌氧生物滤池和膜分离活性污泥法处理，CODCr总去除率高达93%-99%，出水CODCr≤300mg/L，达到GB8978-1996《污水综合排放标准》行业二级排放标准，顺利通过当地环保部门的验收。     

厌氧发酵处理味精废水中氯离子的影响

在3L 的CSTR 型厌氧反应器中研究了味精废水厌氧处理中氯离子毒性的反应。试验证明,已中毒的厌氧过程只要Cl~-浓度降至抑制限以下,厌氧过程就可在15～20d 内恢复,在恢复期间加入新污泥有利于恢复过程。保持足够大的SRT 和污泥浓度对于处理含有毒物的废水很有效。对本研究,SRT 得大于20d,污泥浓度在15～24g/L 左右就可达到较好的处理效率。Cl~-的抑制浓度对污泥浓度分别为24.28g/L,15.18g/L 和6.07g/L 时,Cl~-的抑制浓度分别是7750mg/L,7250mg/L和6300mg/L。此外,本文提出以I=S_(Cl)/X_v~n作为判断Cl~-抑制的指标。当COD 去除率大于80%时,n=0.1519。因此,要使过程的COD 去除率分别大于80%,85%和90%时,I 就得分别小于4.7,4.1和3.6。并且污泥浓度必须大于6.07g/L。     

浓缩法测定水中痕量汞

采用浓缩消解、冷原子吸收的方法，测定水中的痕量汞，通过多次实验，测定方法的准确性和精密度都较高，说明该方法可行。